Transistor ignition system



June 28, 1960 F. s. KERR 2,943,131

TRANSISTOR IGNITION SYSTEM 2 Sheets-Sheet 1 Filed July 21, 1958 IN VENTOR ATTORN F. s. KERR 2,943,131

JLme 28, 1960 TRANSISTOR IGNITION SYSTEM 2 Sheets-Sheet 2 Filed July 21, 1958 FIC3-'7.

VOLTAGE.

REQLJI REMENT ENGINE SPEED-N FIG; 8 56 AvAn AS| E VOLTAGE VOLTAGE SPARK PLUG REQU I REM ENT ENGINE SPEED-N A SPARK VOLTAGE 5 9 (SPARK PLUG) I c VOLTAGE BUILD-UP INVENTOR.

TRANSISTOR IGNITION SYSTEM- Fred S. Kerr, Royal Oak, Mich., assignor to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Filed July 21, 1958, Ser. No. 749,867

23 Claims. (Cl. 123--148) The present invention relates to an improved ignition system in which semi-conductor type electrical transistors are employed to replace conventional ignition contacts. In its operation the system affords an improved output sparking voltage from a coil to the high tension distributor unit of an automotive installation, in which coil voltage loss, heretofore experienced as engine speed increases, is compensated for, the coil output being at all times matched with engine requirements.

An operational drawback characteristic of present day automotive ignition circuits, characterized by an engine driven circuit breaker, a coil and a rotary distributor and spark plug system, has resided in the fact that in order to assure proper output voltage, as determined by the spark plug requirements in any given elevated increment or segment of the engine speed range, the coil of the system must be over-saturated at low engine speeds. This over-saturation ultimately causes breakdown of insulation and the like to reduce'the coil capacity to such an extent that its'output voltage-engine speed curve may drop below the cor-responding voltage-speed curve representing spark plug requirement. Thus the engine will miss in any such higher speed segment of the speed range in which output voltage is less than the plug requirement.

It is therefore a general object of the invention to provide a transistor type ignition system or circuit, in which coil output is properly correlated with spark plug requirements throughout the entire range of engine speeds. As a result, the voltage-speed curve representing coil output made available by the improvement closely follows or parallels the curve of spark plug voltage requirement, with a substantially constant and predetermined safetyfactor at any given speed. 1

It thus further follows that, in addition to avoiding a deficiency of available voltage in any segment of the speed range, the system also never generates a voltage which is excessive in nature, such as is the case in present ignition systems, with the deteriorative effects mentioned above.

In accordance with the invention a pair of electrical transistors are employed and control voltage is applied periodically to the base terminal of one thereof through the agency of an engine driven switch which may be similar to the usual circuit breaker. The control voltage to the base terminal of the other transistor is governed in accordance with engine speed change to accomplish the speed compensated or matched ignition operation referred to above.

Another object is to provide a transistor type ignition system, featuring a pair of electrical transistors connected in an improved circuit with a coil and source of voltage supply, in which unnecessary sparking time after an ignition period adequate for proper firing is avoided, with ice .2 which two semi-conducting transistors, as of the well.- known germanium or silicon, type, are employed. One of these transistors has a control voltage supplied to its base under the, controlof a cam driven switch, interrupting the control current in synchronism with engine speed, and the other transistor is controlled, as regards the'flow of input voltage therethrough, by a further switch opera,- tionally coupled with the starting switch of the automotive ignition system. A control voltage to the base of this second transistor is supplied by an appropriate pulse signal device sensitive to or responsive to engine speed, and as the result a coil input voltage is built up, by the transistor system which at all times matches spark plug requirement. 7 p

Another object in this respect is to providefa system in which transistors of the P-N-P type and the N-P-N type are employedin different parts thereof. In certain of the embodiments herein described, provision is made for an optional reversal of their respective polarities, if desired; and in another embodiment it is contemplated that transistors of like polarity be employed; In any adaptation, the circuitry iswell adapted for interconnection with and control by existing ignition system components, for good grounding on the vehicle chassis, etc.

The foregoing as well as other objects will become more apparent as this description proceeds, especially when considered in connection with the accompanying drawings illustrating preferred embodiments of the invention, wherein: i

Figs. 1 and 2 are alternative schematic wiring diagrams of systems incorporating the principles of the invention;

Figs. 3 and 4- are partial schematics showing; further modifications of the systems of Figs. 1 and 2, respectively, by eliminating certain of their components;

Fig. 5 is a more or less schematic view of an engine driven mechanism for timing a make and break switch which governs the intermittent supply of control voltage to one of'the transistors of the system;

Fig. 6 is a schematic wiring diagram showing the mode of interconnecting a further control switch of the present system in the existing starting motor circuit of an automotive installation, for the purpose ofmomentarily closing that switch with the energization 'of the starting motor; i

Fig. 7 is a graph depicting voltage-engine speed curves of existing ignition systems, and showing the effect of insufiicient available coil voltage at increased speed;

Fig. 8 is a voltage-engine speed graph comparing available coil voltage and required spark plug voltage as the result of the operation of the improved system;

Fig. 9 is a graph plotting spark plug applied-voltage against time to illustrate a further operational advantage of the improved system in regard to the duration of spark plug ignition time; and

Fig. 10 is a schematic wiring diagram of a still further modification of the system, in which two transistors of like type and polarity are employed.

Referring first to Fig. l of the drawings, a schematic wiring diagram of one embodiment of a transistor-type ignition system it) according to the invention, the reference numeral 11 designates the usual ignition coil having a primary winding 12 supplied under the control of the system (in a manner to be described) and asecondary winding 13, the output of which is applied to the spark plugs of the engine, as through the agency of a high tension spark plug distributor mechanism, schematically shown and generally designated 14, which is grounded to the chassis in the usual manner.

' The reference numeral 16 indicates a transistor of the known semi-conductor type, and the reference numeral 17 denotes a first switch governing the supply of D.C. current to the transistor 16 from a grounded battery 18,

To this end theemitting junction or terminal element E of the transistor 16 is connected to the negative terminal of battery 18, and switch 17 is wired in shunt relation to the transistor 16 from the negative terminal of battery 18 to a common terminal of a resistor-capacitor combination 19, which combination is connected electrically to the collecting terminal or junction C of transistor 16. The RC combination or network includes a grounded resistor 20 and parallel capacitor 21. The base terminal B of transistor 16 is connected by a. lead 22 with a pulse sensing device 24 associated with the output side of the coil 11, for a purpose to be described.

The device 2 is a conventional one, of which a number are available, acting to pick up an electrical pulse each time a plug of the spark plug and distributor system 14 is fired, and to apply it as a control voltage to the base of transistor 16. w p

The reference numeral 26 designates a second transistor of polarity opposite that of the transistor 16. That is, if transistor 16 is a PNP type, the transistor 26 will be an N-P-N type, and vice versa. Transistors 16 and 26 are shown as combining an emitting junction E and a collecting junction C in the same. unit with a control base B. Appropriate changes in the polarity of necessary connections are such as are well known to those skilled in the art.

A second and driven switch 27 governs the supply of control voltage to the base B of transistor 26 from the collecting junction C of transistor 16, or direct from the battery 18 and resistor-capacitor combination 19, depending upon whether switch 17 is open or closed. Switch 27 is mechanically controlled by cam provisions driven in synchronism with the engine, such as are illustrated in Fig. and will hereinafter be described.

The first mentioned switch 17 is operationally connected with the key or similarly controlled starter switch of the installation, in the manner illustrated in Fig. 6 and to be hereinafter described, so that switch 17 is closed only momentarily or for the period of time that the switchfor the starting motor of the engine is closed and the engine is being cranked in starting.

The emitter element or junction E of transistor 26 is connected to the grounded battery 28 with polarity as shown, and the collecting element or junction C of transistor 26 may be connected, as through a diode type rectifier 29, to the input side of the primary winding 12 of coil 11. Here it may be noted that although two batteries 18 and 28 are shown in the circuit of Fig. 1, a single battery will suflice and the battery'ls may be eliminated, for example, by making appropriate connections of the other battery 28 to the resistance-capacity network 19, transistor 16 and switch 17, such as will be apparent to those skilled in the art. The same applies to the circuit of Fig. 2.

The function of the diode 29 is simply to reduce the peal -to-peak voltage across transistor 26 by eliminating its negative peaks.

A capacitor 30 may be connected in parallel with the series-connected transistor 26 and diode 29 to the input side of coil primary 12, although if this capacitor is employed at all it may be inserted in a number of places in the circuitry.

Referring now to Fig. 5, the closing and opening of switch 27 is eifected in synchronization with engine speed by a make and break cam mechanism shown in that figure, generally designated 32. This may be very similar to the circuit breaker operating in a conventional ignition system, including a cam 33 driven from the engine by a suitable shaft 34. A contactor arm 35 is pivoted at 36 on an appropriate fixed support 37, being provided with an insulating follower element 38 which engages the surface of cam 33, and being spring-urged for such engagement in a Well known manner. Arm 35 carries a contact point 39 engageable under the control of cam 33 with a fixed contact 40, thereby to complete an electrical circuit through the contact arm 35 between leads 41 and 42.

As shown schematically in Fig. 6, the other, starter controlled switch 17 is mechanically coupled to the starting switch and mechanism for the engine. Thus, a starter relay 43 has a contact 44 which is closed in the usual way upon energization of a coil 45 which is connected by a lead 46 to the starting switch (not shown) and a starter circuit 47 to the starter motor 48 is energized from a battery source (which will be the battery 28 of Fig. 1) when contact 44 is closed. The starter contact 44 is mechanically coupled to the contact of switch 17, to complete a transistor shunting circuit from battery 18 when closed, and when open to cause operating voltage to be applied to the emitter of transistor 16, for a flow through the latter when control voltage is applied to its base.

In the operation of the system of Fig; 1, when the starter switch 43 is closed, the transistor switch 17 is also closed, and remains so until the engine fires and switch 43 is opened. Upon closing of switch 17, the transistor 16 is short circuited and current flows from battery 18 to the grounded resistor-capacitor combination 19. As the engine is being cranked by the starter motor 48, the second, engine driven switch 27 alternately opens and closes, and thereby permits a flow of control current to the base of the other transistor 26 when closed.

Upon the last named flow of control current, battery currentwill flow from battery 28 to the emitting side of transistor 26, through the latter and diode 29 and through primary winding 12 of coil 11.

As the engine coupled switch 27 opens, current ceases to flow through transistor 26 and the primary winding 12 of coil 11, causing a collapse of the magnetic field of the coil, with a consequent generation of voltage across secondary winding 13 of coil 11. This causes a spark at one of the plugs of the sparking system 14.

As the engine starts to fire and the starter motor switch 43 is now released, the switch 17 opening concurrently therewith, the resistance-capacity network 19, charged by battery 18 while switch 17 was closed in starting, has its charge now used in part to cause a timed flow of current through engine driven switch 27 and to the base of transistor 26, thus controlling current flow through coil winding 12 as previously described.

The base of transistor 16 is responsive to pulse signals sensed at the device 24 which are related in frequency to engine speed. Accordingly, as engine speed increases the average current flow through transistor 16 is increased, causing a greater voltage application across the resistance capacitor network 19. As the voltage across this combination increases, still more current will flow into the base of transistor 26, permitting more current to flow from battery 28 through the last named transistor, thence through winding 12 of coil 11. This increases the voltage output of the coil and, therefore, the energy available for sparking at 14.

An alternative system is shown in Fig. 2 of the drawings, in which corresponding and correspondingly functioning components are designated by corresponding refference numerals and require no further detailed explanation. It is perhaps to be preferred over the form of Fig. l, in that it employs an easily made grounded connection, at 50, of the transistor 26 to the chassis of the vehicle. The rectifier diode 29 is here shown as being connected on the output side of primary coil winding 12, rather than on the input side, and the optional capacitor 30 is differently connected. However, in other respects the circuitry is essentially the same as in Fig. 1.

As is suggested in the above, and in view of the availability of increasing improved transistors, either the capacitor 30 or the diode 29, or both, appearing in Figs.

1 and 2, may be eliminated, and the circuit or system will still satisfactorily perform its compensated output generating function. Thus Fig 3 is a partial schematic view of an arrangement corresponding to that of Fig. 1, but lacking the capacitor 30 and rectifier 29 in question and having. the collecting terminal C of transistor 26 direct-connected to the input side of the coil primary 12.

On the other hand, Fig. 4 of the drawings is a partial schematic showing elements of the system of Fig. 2 correspondingly altered in their wiring to eliminate both the capacitor andv diode, with the emitting electrode E of transistor 26 direct-connected to the common terminal of the windings 12, 13 of coil 11. In other respects, the circuits of Figs. 3 and 4 correspond with those of Figs. 1 and 2, respectively, save that certain components have been omitted for simplicity.

The advantages of the improved transistor-type ignition system, as compared with existing ignition systems, are graphically depicted in Figs. 7, 8 and 9 of the drawings. In Fig. 7, a standard curve 52 of spark plug requirements is plotted in terms of approximate voltage and engine speed N; and the solid and dotted line curves 53 show available coil voltages, in each instance characteris tic of the output of an existing conventional ignition system. It is seen that the available coil voltage must be excessive, as in the left hand, low speed portion 54 of the range of the solid line curve 53, in order'that a sufficient amount of current be made available in a higher speed segment of the speed range, as instanced at X.

This over-saturation to produce proper spark plug requirement at X causes breakdown of insulation and reduction of capacity of the coil to the extent that in time the available voltage curve 53 may drop to what is shown in dotted line in Fig. 7. It is seen that output voltage falls beneath what is required by curve 52 in the higher speed range or zone marked D. Though the segmental zone D is exaggerated in length for clarity, there is a considerable range of higher engine speeds during which insuflicient voltage exists to satisfy spark plug requirements, and missing of the engine will occur in this range.

By contrast, the improved transistor type system produces the operation shown in Fig. 8. The excessive, over-saturating of voltage generated in the portion 54 of the solid line curve 53 of Fig. 7 is eliminated and the improved available voltage curve here designated 56, closely follows the curve 57 of required spark plug available voltage, with a predetermined and desiredly constant safety factor F in excess of the requirements. The system never generates available voltage which is either insufiicient or execssive in nature, as in the operation of the coils of present day ignition systems.

Fig. 9 is a voltage-time graph, the curve of spark plug voltage build-up being designated '59. Actual sparking starts at the peak A, with decay of the spark through the zone B. The spark actually remains alight during the continuing zones C and D, due to coil capacity, but time duration represented by time zone C is all that is required for the spark to actually remain alight in order to secure proper ignition. The zone D to the right of zone C represents wholly unnecessary sparking time. This excessive sparking time for the most part isv eliminated in the operation of the improved system, although a certain safety factor of time duration will be allowed to remain in the zone Dv Fig. 10 of the drawings illustrates a still further alternative in the composition and wiring of a system of the invention. It differs from the adaptations shown in Figs. 1, 2, 3 and 4 in the fact that its transistors 16 and 2e are of like type and polarity, whereas in the earlier forms the corresponding transistors are of opposite polarity; and in the fact that the modification of Fig. 10 eliminates the need for two batteries.

As shown in 10, the transistors 16, 26 are of the P-N-P polarity; however, with applropriate'changes in polarity of connections, transistors of the NAP-N type may be employed.

Inasmuch as the composition of the system of Fig.

10 employs parts corresponding to thoseshown in Figs. 1, 2, 3 and 4, corresponding reference numerals. are employed for simplicity; and further unnecessary description is dispensed with. However, it will be: noted that the single battery 18 of Fig. '10 is grounded and has its positive terminal connected both to the resistor-capacitor network 19, and to the primary winding 12 of coil 11. 19 is connected to the emitter electrode of transistor 16, whose collector electrode is grounded and whose base is wired to the pulse sensing device 24 in the manner of the other forms.

Transistor -2.6 is connected to the common terminal of the windings of coil 11, with its base terminal connected through switch 27 to the emitter electrode of transistor 16; and the switch 17 is placed between the last named terminal in a line including a resistor 60.

In operation, the system of Fig. 10 has the speed matched sparking characteristics described above, in. addition to its advantage of employing but a single battery.

The drawings and the foregoing, specification constitute a description of the improved transistor ignition system in such, full, clear, concise and exact terms-as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims. i

What I claim as my invention is: I 1. An engine ignition. system. comprising a coil to provide output sparking signals at a rate varying with en:

ginespeed, a pair of electrical transistors each having input, base and output terminals, the output. terminal of one. of said transistors having n'1eansv to electrically connect the same to the base terminal of the other, adevice electrically sensitive to said coil; output signals having means electrically connecting the same to the base terminal of said other transistor to apply control voltage thereto in accordance with engine speed, means elect-ricallyconnecting one of said transistors to said coil, means. to interrupt flow of control current from one of said transistors to the other in timed relation to engine speed, and means to apply electrical input potential to at least one of said transistors.

2. An engine ignition system comprisinga coil to provide output sparking signals at a rate varying with; en; gine speed, a pair of electrical transistors each having input, base and output terminals, the output terminal of one of said transistors having means to electrically conmeet the same. to the base terminal of the other, a device electrically sensitive. tov said coil, output signals having means electrically connecting'the same to the base terminal of said other transistor to apply control voltage thereto in. accordance with engine speed, means electrically connecting said other transistor to said coil, means to interrupt flow of control current from one of said transistors to the other in timed relation to engine speed, and means to apply electrical input potential to at least one of. said transistors.

33. An engine ignition system comprising a coil to provide output sparking signals at a rate varying with engine. speed, a pair of electrical transistorsv each having input, base and output terminals, the output terminal of one of said transistors having means to electrically connect the same to the base terminal of the other, a device electrically sensitive to said coil. output signals having means electrical-1y connecting the same to the base terminal of said other transistor to apply control voltage thereto in accordance with enginev speed, means electrically connecting one of said transistors. to said coil, the output-to-base terminal connection of said transistors including means. to interrupt flow of control current from one of said transistors to the other in timed relation to engine speed, and means to apply electrical input potential to at, least one of said transistors.

. 4. An engine ignition system; comprising a coil to provide outputfsparking signals at a rate varying with eu- The opposite terminal of the resistor-capacitor unit 7 gine speed, a pair of electrical transistors each having input, base and output terminals, the output terminal of one of said transistors having means to electrically connect the same to the base terminal of the other, a device electrically sensitive to said coil output signals having means electrically connecting the same to the base terminal of said other transistor to apply control voltage thereto in accordance with engine speed, means electrically connecting one of said transistors to said coil, the output-tobase terminal connection of said transistors including a'resistance capacity network and means to interrupt flow of control current from one of said transistors to the other in timed relation to engine speed, and means to apply electrical input potential to at least one of said transistors. 1

5. An engine ignition system comprising a coil to provide output sparking signals at a rate varying with engine speed, a pair of electrical transistors each having input, base and output terminals, the output terminal of one of said transistors having means to electrically connect the same to the base terminal of the other, a device electrically sensitive to said coil output signals having means electrically connecting the same to the base terminal of said other transistor to apply control voltage theretoin accordance with engine speed, means electrically connecting one of said transistors to said coil, means to interrupt flow of control current from one of said transistors to the other in timed relation to engine speed, and means to apply electrical input potential to at least one of said transistors, said transistor-to-coil connection being made at the input side of said coil.

6. An engine ignition system comprising a coil to provide output sparking signals at a rate varying with engine speed, a pair of electrical transistors each having input, base and output terminals, the output terminal of one of said transistors having means to electrically connect the same to the base terminal of the other,- a device electrically sensitive to said coil output signals having means electrically connecting the same to the base terminal of said other transistor to apply control voltage thereto in accordance with engine speed, means electrically connecting one of said transistors to said coil, means to interrupt flow of control current from one of said transistors to the other in timed relation to engine speed, and means to apply electrical input potential to at least one of said transistors, said transistor-to-coil connection being made at the output side of said coil.

7. An engine ignition system comprising a coil to provide output sparking systems at a rate varying with engine speed, a pair of electrical transistors each having a base and emitter and collector elements, mean's connecting one of said transistors to said coil and connecting the collector element of the other transistor to the base. of said one transistor, means to electrically energize the emitter elements of said transistors, and means connected to the base of said other transistor and electrically sensing said coil output signals to apply control voltage to said last named base at a rate varying with engine speed.

8. An engine ignition system comprising a coil to provide output sparking systems at a rate varying with engine speed, first and second electrical transistors each having a base and emitter and collector elements, means connecting said first transistor to said coil and connecting the collector element of said second transistor to the base of said first transistor, including a current interrupting device and a capacity-resistance network in said last named connection, means to electrically energize the emitter elements of said transistors, and means connected to the base of said second transistor and electrically sensing said coil output signals to apply control voltage to said last named base at a rate varying with engine speed.

9. An engine ignition system comprising a coil to provide output sparking systems at a rate varying with engine speed, first and second electrical transistors each having a base and emitter and collector elements, means connecting said first transistor to said coil and connecting the collector element of said second transistor to the base of said first transistor, means to electrically ener-' gize the emitter elements of said transistors, and means connected to the base of said second transistor and electrically sensing said coil output signals to apply control voltage to said last named base at a rate varying with engine speed, said transistor-to-coil connection including a capacitor.

10. An engine ignition system comprising a coil to provide output sparking systems at a rate varying with engine speed, first and second electrical transistors each having a base and emitter and collector elements, means connecting said first transistor to said coil and connecting the collector element of said second transistor to the base of said first transistor, means to electrically energize the emitter elements of said transistors, and means connected to the base of said second transistor and elec trically sensing said coil output signals to apply control voltage to said last named base at a rate varying with engine speed, said transistor-to-coil connection including a capacitor and a rectifier electrically connected to one another.

11. An electrical engine ignition system comprising a coil to provide output sparking signals at a rate varying with engine speed, a first transistor having a base and emitter and collector elements, one of which elements is electrically connected to said coil unit and the other of which is connected to a voltage source, a second transistor having a base and emitter and collector elements, one of which elements is connected to a voltage source and the other of which has means electrically connecting the same to the base of said first transistor, including a current interrupter operated in timed relation to engine speed, and a device electrically sensitive to said coil output signals having means electrically connecting it to the base of said second transistor to apply control impulses thereto and thereby increase current flow through said second transistor in accordance with engine speed.

12. An electrical engine ignition system comprising a coil to provide output sparking signals at a rate varying with engine speed, a first transistor having a base and emitter and collector elements, one of which elements is electrically connected to the input terminal of said coil unit and the other of which is connected to a voltage source, a second transistor having a base and emitter and collector elements, one of which elements is connected to a voltage source and the other of which has means electrically connecting the same to the base of said first transistor, including a current interrupter operated in timed relation to engine speed, and a device electrically sensitive to said coil output signals having means electrically connecting it to the base of said second transistor to apply control impulses thereto and thereby increase current fiow through said second transistor in accordance with engine speed.

13. An electrical engine ignition system comprising a coil to provide output sparking signals at a rate varying with engine speed, a first transistor having a base and emitter and collector elements, one of which elements is electrically connected to the output terminal of said coil unit and the other of which is connected to a voltage source, a second transistor having a base and emitter and collector elements, one of which elements is connected to a voltage source and the other of which has means electrically connecting the same to the base of said first transistor, including a current interrupter operated in timed relation to engine speed, and a device electrically sensitive to said coil output signals having means electrically connecting it to the base of said second transistor to apply control impulses thereto and thereby increase current flow through said second transistor in accordance with engine speed.

14. An electrical engine ignition system comprising a coil to provide output sparking signals at a rate varying with engine speed, a first transistor having a base and emitter and collector elements, one of which elements is electrically connected to said coil unit and the other of which is connected to a voltage source, a second transistor having a base and emitter and collector elements, one of which elements is connected to a voltage source and the other of which has means electrically connecting the same to the base of said first transistor, including a current interrupter operated in timed relation to engine speed, means to interrupt the supply of voltage to said second transistor, and a device electrically sensitive to said coil output signals having means electrically connecting it to the base of said second transistor to apply control impulses thereto and thereby increase current flow through said second transistor in accordance with engine speed.

15. An automotive engine ignition system for the generation of signals Whose electrical potential bears, over a Wide range of engine speeds, a predetermined substantially constant proportionality to required spark plug firing potential, comprising a unit to provide output signals upon alteration of an electrical input potential thereto, and a switch controlled transistor circuit electrically sensitive to engine speed change and electrically connected to said unit to so alter its input signal, comprising a first electrical transistor having a control base and means electrically connecting said transistor to said unit and to a voltage source, a second electrical transistor having a control base and means to electrically connect the same to a voltage source and to connect its output side to said control base of said first transistor, including an engine driven switch, and a device electrically connected to the control base of said second transistor to supply control impulses thereto, said device being electrically sensitive to said output signals of said unit to vary said control impulses in accordance with engine speed.

16. An automotive engine ignition system for the generation of signals Whose electrical potential bears, over a wide range of engine speeds, a predetermined substantially constant proportionality to required spark plug firing potential, comprising a unit to provide output signals upon alteration of an electrical input potential thereto, and a switch controlled transistor circuit electrically sensitive to engine speed change and electrically connected to said unit to so alter its input signal, comprising a first electrical transistor having a control base and means electrically connecting said transistor to said unit and to a voltage source, a second electrical transistor having a control base and means to electrically connect the same to a voltage source and to connect its output side to said control base of said first transistor, including an engine driven switch, a switch electrically connected to said second transistor to control the flow of voltage therethrough from said source, and a device electrically connected to the control base of said second transistor to supply control impulses thereto, said device being electrically sensitive to said output signals of said unit to vary said control impulses in accordance with engine speed.

17. An engine ignition system to produce ignition voltage matched to and varying in accordance with engine speed, comprising a coil unit to produce output signals, a circuit connected to said coil unit and including an electrical transistor, and means periodically applying control voltage to the base of said transistor in'timed relation to engine speed as to frequency, and means sensitive to said output signals and operatively connected to said transistor to determine the value of said control voltage.

18. An engine ignition system to produce ignition voltage matched to and varying in accordance with engine speed, comprising a coil unit to produce output signals, a circuit connected to the input side of said coil unit and including an electrical transistor having a base and emitting and collecting elements connected to said coil and to a source of potential, respectively, and means periodically applying control voltage to the base of said transistor in timed relation to engine speed as to frequency, and means sensitive .to said output signals and operatively connected to said transistor base to determine the value of said control voltage.

19. An engine ignition system to produce ignition volt-v age matched to and varying in accordance with engine speed, comprising a coil unit to produce output signals, a circuit connected to said coil unit and including a pair of electrical transistors of opposite polarity, means periodically applying control voltage to one of said transistors in timed relation as to frequency with engine speed, and means sensitive to said output signals and operatively connected to the other transistor to determine the value of said control voltage.

20. An engine ignition system to produce ignition voltage matched to and varying in accordance with engine speed, comprising a coil unit to produce output signals, a circuit connected to said coil unit and including a pair of electrical transistors of like polarity, means periodically applying control voltage to one of said transistors in timed relation as to frequency with engine speed, and means sensitive to said output signals and operatively connected to the other transistor to determine the value of said control voltage.

21. In an internal combustion engine ignition system having means for intermittently creating a voltage output in timed relation to the speed of said engine, means for sensing said timed voltage output and creating in turn a signal voltage, and means operatively connected to said first mentioned means and responsive to said signal voltage for determining the value of said timed voltage output.

22. In an internal combustion engine ignition system having means for intermittently creatinga voltage output in timed relation to the speed of said engine, means for sensing said timed voltage output and creating in turn a signal voltage, and means operatively connected to said first mentioned means and responsive to said signal voltage for determining the value of said timed voltage output, said last named means comprising an electrical transistor.

23. In an internal combustion engine ignition system having means for intermittently creating a voltage output in timed relation to the speed of said engine, means for sensing said timed voltage output and creating in turn a signal voltage, and means operatively connected to said first mentioned means and responsive to said signal voltage for determining the value of said timed voltage output, said last named means comprising an electrical resistor, and its operative connection to said first named means including means connecting its emitter to the output of said output-creating means and means connecting its control base to said sensing means to receive said signal voltage.

References Cited in the file of this patent UNITED STATES PATENTS Giacoletto Mar. 17, 1959 

